1. Field of the Invention
The present invention is generally related to an oil draining system for an outboard motor and, more particularly, to a draining system that provides an oil drain opening at a location which prevents oil from being spilled on other surfaces of the outboard motor during the oil draining procedure.
2. Description of the Prior Art
Internal combustion engines require lubrication to prevent excessive wear and damage to portions of the engine that are disposed in sliding association with other components. In four cycle engines, it is common and well known to use an oil sump to contain a quantity of oil that is conducted under pressure to various portions of the engine at where frictional contact between sliding components occurs. Four cycle engines used in outboard motors similarly require an oil sump to contain a quantity of liquid oil that is used for these purposes. Draining oil from an outboard motor can be a difficult and messy task because of the typical locations where drain orifices are placed in known outboard motor applications. Many outboard motor designs provide a drain opening location that makes it very difficult to avoid spilling oil on external surfaces of the outboard motor. Additionally, many locations where drain openings are provided require that a container be continually held in place under the drain opening to receive the used oil being drained from the oil sump.
U.S. Pat. No. 6,099,374, which issued to Watanabe et al on Aug. 8, 2000, describes a lubrication and oil drain system for a four cycle outboard motor. The outboard motor has a multi-cylinder four cycle, internal combustion engine as a power plant. The engine is provided with an oil reservoir in the upper portion of the driveshaft housing and lower unit. Oil is drained back to this oil reservoir by separate drain passages provided in the cylinder head and in the crankcase. In addition, an improved crankcase ventilating system is provided wherein the crankcase ventilating gases follow a circuitous path through the crankcase chamber, camshaft chambers and then to the intake system so as to reduce the emissions of hydrocarbons.
U.S. Pat. No. 5,199,914, which issued to Marsh on Apr. 6, 1993, describes a four stroke outboard motor crankcase oil drain plug opening attachment. The four stroke outboard motor crankcase drain plug opening attachment is described to facilitate drainage and collection of crankcase oil from four cycle outboard motors. The attachment includes a manually operable valve attached by a fitting to the motor drain plug opening. The valve extends to a flexible downspout that extends on downwardly to an auxiliary plug at a bottom end thereof. The valve includes an operator that can be rotated selectively to open and close the valve. The plug can be selectively removed and adds a redundancy feature to facilitate unintentional drainage of oil by operation of the valve. An oil drainage collector including opening and a top end and a bale mounted thereon, may be selectively secured over the valve to facilitate collection of oil. The opening and downspout, and bale are related dimensionally such that the collector container cannot swing free of the downspout when the bale is secured over the valve.
U.S. Pat. No. 4,828,519, which issued to Watanabe on May 9, 1989, describes an outboard motor with an improved lubricating system for the internal combustion engine of the outboard motor. A lubricant sump is positioned beneath the engine and oil is returned to the sump through a drain opening in a spacer plate that separates the engine from the driveshaft housing. The oil sump and drain opening are configured so that oil will not return from the sump through the drain opening to the engine when the outboard motor is laid on its side edge.
U.S. Pat. No. 4,611,559, which issued to Sumigawa on Sep. 16, 1986, describes an outboard motor provided with a four stroke engine. Several embodiments of outboard motors with four cycle engines and improved lubricating systems are described. In all of the embodiments, an oil reservoir is provided in the driveshaft housing and a combined screen and drain plug assembly filters the oil flowing from the oil reservoir to the engine lubricating system and for facilitating servicing of the screen by removal of the drain plug. In one embodiment, the oil reservoir is formed integrally with the driveshaft housing. A pressure relief valve depends in to the oil reservoir and is carried by a plate that connects the engine to the driveshaft housing for facilitating servicing and reducing the likelihood of leakage back of oil to the engine when the outboard motor is tilted up. An improved relief valve screen assembly is also illustrated in one embodiment where the screen may be bypassed if it becomes clogged.
U.S. Pat. No. 6,126,499, which issued to Katayama et al on Oct. 3, 2000, describes an oil pan arrangement for a four cycle outboard motor. The four cycle outboard motor has a water cooled engine and an oil pan that is formed in the upper portion of the driveshaft housing. An exhaust pipe collects exhaust gases from an exhaust guide and delivers to a cavity that is formed in the oil pan by an interior wall thereof. The exhaust pipe does not terminate below the lower surface of the oil pan and idle exhaust gases are delivered between the exterior of the exhaust pipe and interior surface of the oil pan that defines the cavity. These exhaust gases are discharged to the atmosphere through and above the water exhaust gas discharge. The oil pan lower surface has a drain opening that is aligned with a vertical drain opening in the driveshaft housing.
U.S. Pat. No. 4,452,194, which issued to Watanabe on Jun. 5, 1984, describes an outboard motor. A water cooled, four cycle internal combustion engine is particularly adapted for use in an outboard motor. A support plate arrangement is used with the supporting plate extending across the driveshaft housing at its upper end. The engine is supported on the upper side of the supporting plate and an oil pan is supported on the underside of the supporting plate and depends into the driveshaft housing. The construction is such the engine may be removed from the supporting plate without necessitating removal of the oil pan from the supporting plate so as to facilitate servicing. In addition, an oil drain is provided through the supporting plate at such a location so as to insure against leakage from the lubricant from the oil sump back into the engine regardless of whether the engine is in its normal running condition or its tilted up condition. The engine also includes an improved lubricating system for insuring good pressure lubrication of all components while minimizing the number of oil passages and avoiding the use of external oil conduits.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
Known outboard motor oil drain systems typically include an oil drain orifice that is located at a position on the outboard motor which has inherent disadvantages. Many of these oil drain systems require that an oil container be continually held in place near the oil drain opening to receive used oil flowing from the oil drain opening. This makes it difficult to set an oil container on the ground under the outboard motor to receive the oil without continued attention by the operator draining the oil. Other known systems place the oil drain opening at a location which makes it exceedingly difficult to drain all of the oil from the oil sump without spilling some oil on the external surfaces of the outboard motor.
It would be significantly beneficial if an oil drain system for an outboard motor could be constructed in such a way that the person draining the oil can simply place an oil receiving container on the ground under the outboard motor and leave the outboard motor unattended during the draining process. It would be even more beneficial if such a system could be configured in a way that avoids the spillage of oil on any surface of the outboard motor during the oil draining process.
An oil draining system for an outboard motor, made in accordance with a preferred embodiment of the present invention, comprises an oil sump reservoir having a bottom portion and a driveshaft housing in which the oil sump reservoir is disposed. It also comprises an oil drain opening formed in a surface of the outboard motor, the surface being generally horizontal when the outboard motor is attached to a transom of a marine vessel. The oil drain opening is disposed below all other portions of the outboard motor which are intersected by a vertical line through the oil drain opening when the outboard motor is attached to the transom of the marine vessel. As a result, liquid oil draining from the oil drain opening under the force of gravity, along the vertical line, will not contact any other portions of the outboard motor as it passes those portions in a downward direction. This characteristic of the present invention allows the used oil to be received by a container placed on the ground under the outboard motor without the requirement that the person draining the oil either hold the container in place or cause it to be held in place above the ground level or result in spillage of oil on the outer surfaces of the outboard motor.
The surface of the outboard motor, in a preferred embodiment, is a lower surface of a splash plate of the outboard motor. The oil drain opening is laterally offset from all surfaces of the outboard motor which are located in a direction below the splash plate when the outboard motor is attached to the transom of the marine vessel. The oil sump reservoir, in a preferred embodiment, is a separate container which is disposed in a cavity of the driveshaft housing which is shaped to receive the oil sump reservoir. A transition drain conduit has a first end connected in fluid communication with an internal cavity of the oil sump reservoir and the transition drain conduit has a second end located at the oil drain opening.
A protective conduit housing is integrally formed within the structure of the driveshaft housing and has a first end which is shaped to receive the transition drain conduit. It has a second end which serve as the oil drain opening and receives the second end of the transition drain conduit. The protective conduit housing is contained within a protruding rib which is formed as part of the driveshaft housing and which extends from the second end of the protective conduit housing which is proximate the plate portion to the first end of the protective conduit housing which connects to the cavity in the driveshaft housing. The transition drain conduit, in a preferred embodiment, is generally L-shaped and extends from the bottom portion of the oil sump. The transition drained conduit is disposed partially within the sump cavity of the driveshaft housing, external to the oil sump reservoir. A plug is shaped to be received in threaded association by the second end of the transition drain conduit. The oil drain opening contains the second end of the transition drain conduit and is located at a position which is forward of a propeller of the outboard motor when the outboard motor is attached to the transom of the marine vessel. The oil drain opening is located at a port side of the outboard motor when the outboard motor is attached to the transom of the marine vessel.